The present invention relates to a covering wire tightening means or device for composite strings of pianos, and more particularly relates to a means advantageously used for eliminating slack winding of the covering wire on composite strings of pianos in order to improve tonal quality of tones to be generated.
As hereinafter described in more detail, a string for pianos is usually given in the form of a composite string particularly in the bass tone range. Such a composite string includes a core wire and a covering wire wound around the core wire.
It is known that a good tonal quality is obtained when the covering wire is relatively loosely wound around the core wire. However, gaps tend to be left between the wires by such a slack winding. Presence of such gaps generates unnecessary high frequency components when the string is hit by the hammer, thereby having ill influence on tonal quality of the tone to be generated. Therefore, a highly skilled technique is required in order to properly adjust the winding strength of the covering wire.
In order to eliminate such slack winding on a composite string, it is conventional practice to loosen the tuning pin for the ill wound composite string, disengage the composite string from the associated frame pin, twist by hand or suitable pincers the composite string in the winding direction of the covering wire, bring the fastened composite string back into engagement with the frame pin and stretch the composite string by adjusting the tuning pin.
However, strong resistance by the core wire against such twisting makes it quite difficult to successfully adjust the fastening strength of the covering wire in the above-described manner. Slight relaxation of the operator's hands during the adjustment allows easy restoration of the slack winding on the composite string. In addition, space limitation in the piano casing hinder free adjustment of the winding strength by operator's hands.